Aims Second-generation metal-on-metal (MoM) articulations in total hip arthroplasty (THA) were introduced in order to reduce wear-related complications. The current study reports on the serum cobalt levels and the clinical outcome at a minimum of 20 years following THA with a MoM (Metasul) or a ceramic-on-polyethylene (CoP) bearing. Methods The present study provides an update of a previously published prospective randomized controlled study, evaluating the serum cobalt levels of a consecutive cohort of 100 patients following THA with a MoM or a CoP articulation. A total of 31 patients were available for clinical and radiological follow-up examination. After exclusion of 11 patients because of other cobalt-containing implants, 20 patients (MoM (n = 11); CoP (n = 9)) with a mean age of 69 years (42 to 97) were analyzed. Serum cobalt levels were compared to serum cobalt levels five years out of surgery. Results The median cobalt concentration in the MoM group was 1.04 μg/l (interquartile range (IQR) 0.64 to 1.70) at a mean of 21 years (20 to 24) postoperatively and these values were similar (p = 0.799) to cobalt levels at five years. In the CoP control group, the median cobalt levels were below the detection limit (< 0.3 μg/l; median 0.15 μg/l, IQR 0.15 to 0.75) at 20 years. The mean Harris Hip Score was 91.4 points (61 to 100) in the MoM group and 92.8 points (63 to 100) in the CoP group. Conclusion This study represents the longest follow-up series evaluating the serum cobalt levels after 28 mm head MoM bearing THA and shows that serum cobalt concentrations remain at low levels at a mean of 21 years (20 to 24) after implantation. Cite this article: Bone Joint Res. 2020;9(3):145–150.

A male patient aged 69 years suffering from Paget-coxarthrosis with a large distension of the proximal femur was implanted a cementless tumor reconstruction system. The surgical procedure consisted of opening of the femoral shaft with a special drill, insertion of the prosthesis and its anchorage within the healthy distal bone. By this method we were able to save the femoral muscle insertion planes. Twenty-eight months postoperatively the patient is pain-free and very satisfied with the outcome. The X-rays show a good fit of the prosthesis. The Harris Hip Score is now 90.1 points as compared to 46.4 points preoperatively.

Metal-on-metal articulations were reintroduced to reduce polyethylene particle-induced osteolysis. Elevated serum metal levels have been detected at short- and intermediate-term follow-up. There is little knowledge about long-term effects of increased ionic metal generation. Our study was undertaken to provide information about long-term survival, clinical outcome, radiographic appearance, and serum metal concentrations after a minimum 10 years follow-up with a metal-on-metal hip prosthesis: 105 cementless primary total hip prostheses with metal-on-metal articulating surfaces were implanted in 98 patients with a mean age of 56 years. Clinical data, radiographs, and blood samples were obtained at a follow-up visit 10 years after implantation. Serum cobalt and chromium levels were determined with use of atomic absorption spectrometry. General laboratory analyses included a full blood count and kidney function parameters. The Harris score was 92 points and the UCLA score 6 points after 10 years. Small osteolytic lesions and radiolucent lines were found in Gruen's zones 1, 7, 8, and 14. The probability of survival was 98.6%. The median serum cobalt concentration of the 22 patients with their hip replacement as the only source of cobalt was 0.75 microg/L (range, 0.3-50.1 microg/L). No patient was diagnosed with renal insufficiency during the study period. Five patients were diagnosed with a malignancy between surgery and the follow-up. We do not have evidence of an increased rate of primary malignancies nor could we detect renal failure in our study group. Serum metal levels did not differ from short- and intermediate term follow-up values.

In a randomised study, 28 patients with a mean age of 62.2 years (32 to 81) with osteoarthritis or avascular necrosis of the hip received either a ceramic-on-ceramic or a metal-on-metal total hip replacement. Apart from the liners the acetabular and femoral components were made of Ti-Al-Nb alloy. The serum aluminium and cobalt levels were measured before, and at one year after surgery. The 15 patients in the ceramic-on-ceramic group had a median pre-operative aluminium level of 1.3 microg/l (0.25 to 8.4) and a cobalt level below the detection limit. At one year the aluminium level was 1.1 microg/l (0.25 to 2.3) and the cobalt level was 0.4 microg/l (0.15 to 0.7). The 13 patients in the metal-on-metal group had a median pre-operative aluminium level of 1.9 microg/l (0.25 to 4.4) and a cobalt level below the detection limit. At one year the median aluminium level was 0.9 microg/l (0.25 to 3.9) whereas the cobalt level was 1.4 microg/l (0.5 to 10.5). This increase in the cobalt level at one year was significant (p < 0.001). Our findings indicate that ceramic-on-ceramic bearings do not cause elevated levels of serum aluminium in the first post-operative year.

Study Design. A retrospective review. Objectives. To determine the clinical and radiologic outcomes beyond 5 years after anterior cervical discectomy and fusion with allograft and plating. Summary of Background Data. Anterior cervical discectomy and fusion is commonly performed for cervical disc disease. The routine use of allografts and plating, though increasing in popularity, has not been well studied for long-term results and complications. Methods. Seventy-one patients who had anterior cervical discectomy and fusion with allograft and plating an average of 7.2 years prior responded to an invitation to return for a follow-up clinical and radiographic review. Results. At final review, symptom resolution remained greater than 82% and fusion occurred in 92.6% of the disc spaces operated on. No graft extrusion or migration occurred. Based on our strict criteria, the rates of collapse and subsidence were high, at 47.9% (34 patients) overall. However, in only 6 patients (8.5%) did segmental kyphosis result, none of whom required any revision surgery in the follow-up period. Implant complications occurred in 7 patients (9.9%), none of whom required revision surgeries. Adjacent level degeneration occurred in 52 patients (73.2%). Further cervical spine surgeries were required in 14 patients (19.7%), 2 for inadequate decompression, and 12 for adjacent level disease. Segmental and global cervical lordosis was restored and maintained by the surgery over the study period. Conclusions. The use of allografts and plate fixation in combination for anterior cervical discectomy and fusion does not compromise the radiologic and clinical outcomes while providing the advantages of donor site morbidity elimination, restoration of cervical segmental lordosis, and not requiring postoperative immobilization.

STUDY DESIGN:Retrospective review.OBJECTIVES:To review the findings in the cases of spondyloptosis we have treated and to postulate on the possible cause of spondyloptosis.SUMMARY OF BACKGROUND DATA:Spondyloptosis (Grade V spondylolisthesis) is rare, even though spondylolisthesis is a relatively common condition. While it is known that progression to spondyloptosis occurs in patients with developmental spondylolisthesis in their childhood and/or adolescent years, the precise factors leading to progression are not known.METHODS:Between 1979 and 2002, 27 patients with spondyloptosis were treated surgically with L5 resection and reduction of L4 onto S1. During the treatment process, detailed observations of the surgical findings were made through clinical and radiologic means. Six anatomic parameters (pars interarticularis defects, spina bifida of the L5 or sacral segments, dysplasia of the L5-S1 facet joints, L5-S1 disc degeneration, trapezoidal shape of L5, and rounding of the proximal end of the sacrum) were specifically studied.RESULTS:Pars interarticularis defects were present in 24 patients (88.9%), facet dysplasia in 16 patients (59.2%), spina bifida in 24 patients (88.9%), disc degeneration in 25 (92.6%), trapezoidal L5 in 20 patients (74.1%), and rounding of the proximal end of S1 in all 27 patients (100%).CONCLUSIONS:Rounding of the proximal sacral endplate was the only constant abnormal anatomic feature in the patients. Damage to the proximal sacrum and sacral growth plate during late childhood and early adolescence, similar to the epiphyseal injury that produces Blount's disease, and slipped capital femoral epiphysis seem to be key factors permitting the progression of developmental spondylolisthesis to spondyloptosis.

We investigated prospectively the bone mineral density (BMD) of the proximal femur after implantation of a tapered rectangular cementless stem in 100 patients with a mean age of 60 years (16 to 87). It was determined using dual energy x-ray absorptiometry, performed one week after surgery and then every six months until the end-point of five years. The BMD increased significantly in Gruen zones 2, 4 and 5 by 11%, 3% and 11% respectively, and decreased significantly in Gruen zones 1, 6 and 7 by 3%, 6% and 14% respectively, over the five-year period. The net mean BMD did not change over this time period. The changes in the BMD were not confined to the first 12 months after surgery. This investigation revealed no change in the overall periprosthetic BMD, but demonstrated a regional redistribution of bone mass from the proximal to distal zones.

Besides the number of annual total hip arthroplasty (THA) surgeries (11,978 primary THA, 148 implantations per 10(5) inhabitants), little is known about the state of total hip replacement in Austria. We collected information about different aspects of THA treatment regimens. A questionnaire was developed and sent to all chairmen of orthopedic and traumatology departments posing 22 questions regarding type of THA, surgical technique, number of surgeries, data collection, physical therapy and mobilization, length of hospital stay, and recommendations on sport activities as well as activities of daily life. In Austria cementless THA predominates (according to the questionnaire survey 85%). Postoperative mobilization with cementless implants is prescribed as full weight bearing in 52%, partial weight bearing in 42%, and no weight bearing in 6%. The length of hospital stay with cementless insertion is 14.2 days and with cemented implantation 14.9 days; the use of crutches is recommended for 6.0 and 5.4 weeks, respectively. Hip scores for documentation are used before surgery in 65% of orthopedic departments and 13% of traumatology departments and in the postoperative follow-up in 62% and 13%, respectively. In-patient rehabilitation is prescribed by 74% of orthopedic and 26% of traumatology departments. Austria ranks among the top nations in Europe regarding the number of total hip arthroplasty implantations. Documentation is insufficient and needs to be improved. In some aspects of managing patients with total hip arthroplasties there are remarkable differences between orthopedic and traumatology departments.

Der Stand der Hüftendoprothetik in Österreich ist—abgesehen von den Implantationszahlen (11.978 primäre Hüftendoprothesen entsprechend 148 Implantationen pro 105 Einwohner)—weitgehend unbekannt. Ein Fragebogen wurde erarbeitet, um Kenntnisse über verschiedene Aspekte der Hüftendoprothetik zu sammeln.

Umbilical cord serum and corresponding maternal serum of 3 women with uncemented metal-on-metal total hip arthroplasties were analyzed for cobalt and chromium. The women were an average 3.8 (range, 2-5) years after hip surgery. At the time of delivery, the maternal chromium concentrations were 1.6 microg/l, 0.5 microg/l, and 0.9 microg/l, respectively, and the maternal cobalt concentration was 1 microg/l in the first woman and below the detection limit in the other 2 women. Cobalt and chromium concentrations of the 3 umbilical cord sera also were below the detection limit. This indicates that-with regard to the detection limit of our laboratory-we were unable to observe a passage of cobalt and chromium ions from metal-on-metal articulations across the placenta at the time of delivery.

We investigated whether cup inclination influences serum levels of cobalt and chromium after metal-on-metal total hip arthroplasty. Out of a consecutive series, 3 groups of 20 patients each were established according to their cup inclination: greatest inclination (55 degrees -63 degrees, mean 58 degrees), intermediate inclination (44 degrees -46 degrees, mean 45 degrees), and smallest inclination (23 degrees -37 degrees, mean 33 degrees). We did not detect any statistically significant difference of serum cobalt (P = .23) or serum chromium (P = .13) levels between the 3 groups applying the Kruskal Wallis test. However, 3 patients with cup inclinations of 58 degrees , 63 degrees , and 61 degrees exhibited 9.8-53.6-fold elevated cobalt and 9.5-30.5-fold elevated chromium levels when compared with the median concentrations of this trial. We therefore recommend accurate cup placement also for metal-on-metal articulations.

Anterior cervical discectomy and fusion is commonly performed for cervical disc disease. Most studies report that swallowing and voice problems after such surgeries tend to resolve with time and are often of minor significance except in the rare cases of recurrent laryngeal nerve palsies. A retrospective review was performed on patients who had anterior cervical discectomy and fusion by a single surgeon more than 5 years prior, to determine the persistence of swallowing and voice problems in them.Seventy-four patients who had anterior cervical discectomy and fusion with allograft and plating an average of 7.2 years prior responded to an invitation to return for a follow-up clinical review. Emphasis was placed on the symptoms of dysphagia and dysphonia, as related to the index surgery. At final review, persistent dysphagia was present in 26 patients (35.1%). This occurred more frequently in females and in younger patients. Dysphonia at final review persisted in 14 patients (18.9%). This also occurred more commonly in females and in patients in whom possible non-union is present in at least one of the levels operated upon. Problems with singing were present in 16 patients (21.6%) postoperatively, occurring more frequently if the C3/4 disc was included in the surgery and in patients who have had a greater total number of anterior cervical surgeries at the time of review. Dysphonia and dysphagia are persistent problems in a significant proportion of patients, even beyond 5 years after anterior cervical spine surgery.

The number of metal-on-metal bearings used clinically continues to increase, particularly in young, active patients. The single greatest concern with the use of a metal-on-metal bearing continues to be the elevated levels of metal ions measurable in patients' blood and urine following implantation. There are multiple complex issues associated with the analysis of metal ions, including collection techniques, analysis, statistical methodologies, and reporting of results. To date, the literature on this topic has been characterized by significant variability in all of these factors. This paper seeks to establish a consensus among 3 investigators who have been working in this area and to offer guidelines on the complex methodology involved in the evaluation of metal concentration in patients following metal-on-metal hip arthroplasties.

STUDY DESIGN:A retrospective review.OBJECTIVES:To determine the clinical and radiologic outcomes beyond 5 years after anterior cervical discectomy and fusion with allograft and plating.SUMMARY OF BACKGROUND DATA:Anterior cervical discectomy and fusion is commonly performed for cervical disc disease. The routine use of allografts and plating, though increasing in popularity, has not been well studied for long-term results and complications.METHODS:Seventy-one patients who had anterior cervical discectomy and fusion with allograft and plating an average of 7.2 years prior responded to an invitation to return for a follow-up clinical and radiographic review.RESULTS:At final review, symptom resolution remained greater than 82% and fusion occurred in 92.6% of the disc spaces operated on. No graft extrusion or migration occurred. Based on our strict criteria, the rates of collapse and subsidence were high, at 47.9% (34 patients) overall. However, in only 6 patients (8.5%) did segmental kyphosis result, none of whom required any revision surgery in the follow-up period. Implant complications occurred in 7 patients (9.9%), none of whom required revision surgeries. Adjacent level degeneration occurred in 52 patients (73.2%). Further cervical spine surgeries were required in 14 patients (19.7%), 2 for inadequate decompression, and 12 for adjacent level disease. Segmental and global cervical lordosis was restored and maintained by the surgery over the study period.CONCLUSIONS:The use of allografts and plate fixation in combination for anterior cervical discectomy and fusion does not compromise the radiologic and clinical outcomes while providing the advantages of donor site morbidity elimination, restoration of cervical segmental lordosis, and not requiring postoperative immobilization.

BACKGROUND:Systemic cobalt dissemination from the Metasul Co-28Cr-6Mo-0.2C metal-on-metal total hip prosthesis has been demonstrated in the first year after implantation. The aim of this prospective study was to monitor the serum cobalt concentrations in patients during the first five years after total hip arthroplasty with a metal-on-metal articulation. METHODS:A total hip arthroplasty was performed without cement in 100 consecutive patients who had either unilateral osteoarthritis or unilateral osteonecrosis. Fifty patients were randomized to be treated with a metal-on-metal articulation, and fifty patients, with a ceramic-on-polyethylene bearing. The femoral stem was made of a Ti-6Al-7Nb alloy, and the threaded acetabular cup was made of commercially pure titanium. Blood samples were taken before the operation and at multiple time-points for five years after the operation. Serum cobalt concentrations were measured with use of atomic absorption spectrometry. RESULTS:In the metal-on-metal group, the median serum cobalt concentration was 1 micro g/L at one year after surgery and 0.7 micro g/L at five years. The median of the serum cobalt concentrations measured from three to twelve months did not differ from the median of subsequent measurements, with the numbers available. The median serum cobalt level in the control group of patients treated with the ceramic-on-polyethylene articulation was below the detection limit at all time-points. CONCLUSIONS:Systemic cobalt release from Metasul metal-on-metal articulations was demonstrated throughout the five-year study period. The median serum cobalt concentrations were found to be slightly above the detection limit and remained in a constant range. The serum cobalt concentrations did not reflect a so-called run-in wear period of the metal-on-metal articulations.

Background and aims. The knee is one of the most commonly affected joints in haemophilic arthropathy leading to stiffness and disability. It is the aim of this study to investigate the outcome of corrective osteotomies around the knee. Patients and methods. We report on the long-term results of ten osteotomies around the knee for severe haemophilic arthropathy and axial deviation at an average of 7.25+/-1.8 years postoperatively. Seven high tibial (preoperatively 7.2+/-2degrees varus) and three supracondylar osteotomies (preoperatively 7+/-3degrees valgus) were performed on seven patients (three of them bilateral). Results. The clinical score of the Advisory Board of the World Federation of Haemophilia (average 7.4 points preoperatively) remained unchanged in two patients, improved in three patients and deteriorated in five patients. The radiological Pettersson score (average 8.2 points preoperatively) showed a worsening of 2.5 points over the time. Patients reported a subjective improvement for seven osteotomies, with sports activity in three patients, although the range of motion did not change significantly. Total knee arthroplasty was considered to be a failure, i.e. endpoint of follow-up. Six knees were replaced in four patients by total arthroplasty after a mean of 6.6 years. Conclusion. Although survival of osteotomies around the knee in haemophilic arthropathy is lower than in non-haemophilic patients, we think that it is a choice of treatment, which, at least, postpones the indication for total knee arthroplasty in this young patient group.

Study Design. Retrospective case series review. Objectives. To evaluate the outcomes of a new short segment anterior scoliosis technique with complete removal of the discs, bone-on-bone apposition of the vertebral bodies, and dual rod instrumentation. To evaluate a new preop planning technique for scoliosis instrumentation. Summary of Background Data. Scoliosis surgery traditionally was performed via a posterior approach, but anterior scoliosis instrumentation has proven to be superior regarding the amount of curve correction and the number of segments saved from instrumentation. Methods. Thirty-one patients with single curve idiopathic scoliosis less than 75° were operated using the bone-on-bone surgical technique with dual rod instrumentation (Kaneda Anterior Scoliosis System, Depuy AcroMed, Raynham, MA from 1996 until 2001). Average follow-up was 40 months (range 15–77 months). Results. Surgical correction of the major curve averaged 73.9% over the instrumented levels and 51.4% over the entire curve. The average number of discs fused was 4.6 for thoracic curves and 3.3 for thoracolumbar and lumbar curves. There were no implant-related complications or nonunions. The compensatory curves spontaneously improved by an average of 38.6%. Uneventful healing of all fusions occurred—most within 8 to 12 weeks. One compensatory thoracic curve progressed and posterior instrumentation was done 28 months after correction of the major thoracolumbar curve. Conclusions. Surgical correction was achieved in over half the levels that would have been operated by standard posterior segmental fixation. Bony healing due to the bone-on-bone apposition was achieved uneventfully after apical correction of the spinal curvature in all patients. Use of dual rod instrumentation (Kaneda Anterior Scoliosis System) is fundamental in maintaining the correction of the curvature achieved in the operating room. The preoperative planning technique worked well.

PURPOSE:The influence of chronic renal failure on serum cobalt and serum chromium in two patients with metal-on-metal bearing (Metasul) and cementless total hip arthroplasty (Alloclassic) is investigated.METHODS:Serum cobalt and serum chronium levels were determined in the postoperative course using atomic absorption spectrometry.RESULTS:Maximum values are found to be more than 100-fold elevated when compared to the reported median serum cobalt concentrations in patients with the same prosthesis type and no known renal disease.CONCLUSION:Chronic renal failure seems to be responsible for the marked elevation of serum cobalt and serum chromium.CLINICAL RELEVANCE:Despite evidence of adverse health reactions, a possible effect of long-term cobalt and chromium loading cannot be neglected. In our opinion, metal-on-metal bearings in THA should not be inserted in patients with chronic renal failure. Follow-up investigations (serum cobalt, serum chromium, serum creatinine, BUN, echocardiography) should be performed at short intervals.

Fragestellung: Methode: Ergebnisse: Schlussfolgerungen: Klinische Relevanz: Purpose: Methods: Results: Conclusion: Clinical relevance:

Scoliosis seen in the chicken after pinealectomy resembles adolescent idiopathic scoliosis in man. It has been suggested that in both species, deficiency of the pineal hormone, melatonin, is responsible for this phenomenon.In nine patients with adolescent idiopathic scoliosis and in ten age- and gender-matched controls, the circadian levels of serum melatonin and the excretion of urinary 6-hydroxy-melatonin-sulphate, the principal metabolite of melatonin, were determined. There were no statistically significant differences in the secretion of serum melatonin or the excretion of urinary 6-hydroxy-melatonin-sulphate between the patients and the control group. The hypothesis of melatonin deficiency as a causative factor in the aetiology of adolescent idiopathic scoliosis cannot be supported by our data.